JP2005-259439A discloses a fuel cell system with a cathode gas supplying device configured to supply cathode gas (air) to a fuel cell by a compressor by driving the compressor by either anode gas (hydrogen gas) supplied to the fuel cell from a high-pressure tank or an electric motor.
Further, although not directly pertinent to the cathode gas supplying device, JP2003-31244A discloses an anode off-gas circulation device in a fuel cell system. The anode off-gas circulation device includes a compressor configured to reflux anode off-gas discharged from a fuel cell to an anode supply passage and a turbine configured to rotate the compressor by being driven by cathode off-gas discharged from the fuel cell.